A novel near-infrared fluorescent probe with large Stokes shift for biothiols and the application for in vitro and in vivo fluorescence imaging
Biothiols such as cysteine (Cys) and glutathione (GSH) are important reductive species widely spread in liver, heart, brain and so on, which is essential for maintaining the fundamental roles of these organs. Fluorescent detection of biothiols in living organisms is of great importance for exploring the metabolic pathways and the physiological function in living organisms. Most of the near infrared probes for biothiols have small Stokes shift, usually less than 50 nm, which greatly hampered their applications in biological imaging area, herein, a novel fluorescent probe CS-thiols based on CS (Changsha) near infrared dye analogue with large Stokes shift was developed and applied to living animal image. In the presence of biothiols such as Cys, CS-thiols show a broad fluorescence emission at 660 nm and exhibited high selectivity toward biothiols among other amino acid and reactive species. CS-thiols exhibited little toxicity to HeLa cells and was successfully applied to image biothiols in living cells and living animals.